This shape/form is known as Yunomi in Japan; traditionally used for drinking tea.
This is my new favourite cup.
Glazed with a thin nuka (ash) glaze; the ash this time consists of only ash tree and has an addition of 3% bentonite, and I think the spots are from the bentonite.
Recipe for Nuka glaze, cone 10 Oxidation.
Water_1.5 times the weight of dry ingredients. (consistency of full cream milk)
add 3% bentonite to help keep the glaze in suspension.
The downside of bentonite though is, it takes a lot of effort to sieve the first time.